M.H.
My son,about 18mths at the time, went through this and when researching night terrors we found that this usually happens to children who are overly tired. We watched this and the nights that he would have this problem were the days that he didn't nap. We really try hard to get him to nap everyday and we haven't had it come up since. Night terrors are scary and they say to just let them work through it and they will go back to sleep on their own. Which also worked for us but was very hard since a person's first instinct is to pick them up and hold them. Hope this is helpful. Good luck